28 February 2018

Clarification of pull/push test for Nu-Guard® 31

For Nu-Guard® 31 Guardrail Systems to perform as intended, and remain at the correct height, they must be installed in soil conditions that have sufficient strength to support the posts as required.

A push/pull test, to check the post installation strength, is undertaken with an applied load of 12kN at a height of 635 mm. The resulting yield displacement should not exceed 140mm for a BHP at 200 mm, 100mm for a BHP at 400 mm, and 75 mm for a BHP at 600 mm.

There has been some confusion over when this test is required and by whom. To clarify this the push/pull test is run at the discretion of the Installer Designer as per the entity definition in AS/NZS3845.1-2015. It is not a mandatory requirement of either NZ Transport Agency or CSP.

It is also important to remember that these results are not to be used as substitutes for the necessary soil testing (classification and compaction). Soil conditions should meet the requirements of AS/NZS 3845.1:2015, Specification TNZ B/2 - Construction of unbound granular pavement layers and TNZ M/4 - Basecourse aggregate.

For further information please phone CSP on 0800 655 200 or
Email: cspcustomerservice@csppacific.co.nz